Oscillators are widely used in electronic devices to provide reliable clock signals or timing features for other components of the electronic devices. As electronic devices become more complex and shrink in size, operational requirements for oscillators also become more demanding. One of such operational requirements includes noise immunity.
Noise immunity is a particular concern in oscillators that operate at reduced operating voltages. For example, noises coupled from the power bus of an oscillator may cause undesirable glitches or jitters in the oscillator's output. As the operating voltage reduces, such glitches or jitters become noticeable and, under certain circumstances, unacceptable.